Organic Chemistry

Question 1

What is crude oil?

Answer 1

A mixture of different length hydrocarbons

Question 2

What are hydro carbons?

Answer 2

Compounds made up of carbon and hydrogen only

Question 3

What is the simplest homologous series called?

Answer 3

Alkanes

Question 4

What type of bonds do alkanes have?

Answer 4

They have single bonds between all carbon atoms (saturated)

Question 5

What are characteristics of a homologous series?

Answer 5

Similar chemical properties, trends in physical properties, same general formula. All carbon atoms contain 4 bonds.

Question 6

What is the general formula of an alkane?

Answer 6

CnH2n+2

Question 7

Formula for methane

Answer 7

CH4

Question 8

Formula for ethane?

Answer 8

C2H6

Question 9

Formula for Propane?

Answer 9

C3H8

Question 10

What is the formula for Butane

Answer 10

C4H10

Question 11

What is the formula for Pentane?

Answer 11

C5H12

Question 12

What does the molecular formula do?

Answer 12

Shows the number of atoms of each element present in the compound

Question 13

What does structural formula do?

Answer 13

Shows the arrangement of atoms in a molecule in simplified form

Question 14

What do display formulas do?

Answer 14

Shows every atom and every bond present in the molecule

Question 15

What does empirical formula do?

Answer 15

Shows the simplest ratio of the atoms of each element present in a compound

Question 16

As the number of carbon atoms increase, what do we see?

Answer 16

Boiling point increases
Stronger attractive forces between molecules
More energy required to overcome forces
Less volatile as chain length increases
become more viscous
Darker in colour
Burn less easily

Question 17

What are structural isomers?

Answer 17

Compounds with the same molecular formula - but different structures and they must have the same number of each atom

Question 18

What is substitution?

Answer 18

One atom is swapped with another atom

Question 19

What condition is needed for substitution?

Answer 19

UV light

Question 20

What is combustion?

Answer 20

A reaction where the hydrocarbon is burned in oxygen to release energy when used as fuel

Question 21

what does complete combustion always produce?

Answer 21

Carbon dioxide and water

Question 22

Where does a short chain hydrocarbon condense in a fractional distillation column?

Answer 22

The top sections

Question 23

A hydrocarbon chain catches fire very easily. Does it have a short or long chain?

Answer 23

Short

Question 24

As chain length increases, what happens to its viscosity?

Answer 24

It increases

Question 25

As chain length decreases, what happens to its boiling point?

Answer 25

It decreases

Question 26

What causes incomplete combustion?

Answer 26

Lack of oxygen

Question 27

Products of incomplete combustion?

Answer 27

Carbon monoxide and water

Question 28

What is fractional distillation used for in organic chemistry?

Answer 28

Separating gases

Question 29

Why are different alkenes separated in fractional distillation?

Answer 29

Heat (different boiling points)

Question 30

What must happen to the crude oil before fractional distillation?

Answer 30

They must be heated until hydrocarbons vaporise

Question 31

What are alkenes?

Answer 31

Alkenes are hydrocarbons made from cracking alkanes

Question 32

What kind of bond do alkenes have?

Answer 32

Double bond between 2 carbon atoms (unsaturated)

Question 33

What is the general formula for Alkenes?

Answer 33

CnH2n

Question 34

What are alkenes used to make?

Answer 34

Polymers

Question 35

Are alkanes or alkenes more reactive?

Answer 35

Alkenes

Question 36

What is the test for alkenes?

Answer 36

Add bromine water Alkene = orange to colourless Alkane = stays orange

Question 37

What does cracking do?

Answer 37

Produces a smaller alkane and a smaller alkene

Question 38

Is there a greater supply of longer or shorter chain hydrocarbons?

Answer 38

Longer

Question 39

What chain has more demand in fuels?

Answer 39

Short chain

Question 40

What is there a big demand for alkenes to make?

Answer 40

Polymers

Question 41

What is significant about atoms when cracking a hydrocarbon?

Answer 41

No atoms are lost (allows us to write balance symbol equations)

Question 42

How is cracking achieved?

Answer 42

Large hydrocarbons broken down by heating over a hot catalyst

Question 43

What are polymers?

Answer 43

Large molecules made of 100s of repeating small molecules called monomers

Question 44

What are alkanes used as?

Answer 44

Monomers

Question 45

What are polymers used to make?

Answer 45

Plastics

Question 46

How do we make polymers?

Answer 46

Process called addition polymerisation

Question 47

What are 2 changes that occur during polymerisation?

Answer 47

1 Bond in double bonds break, many monomers join to make one long chain.

Question 48

Why is the disposal of plastics (polymers) difficult?

Answer 48

They’re unreactive (non bio degradable) and cannot be broken down by bacteria - last 1000s of years!

Question 49

What are advantages of burning plastics? (Polymers)

Answer 49

Saves up space and a source of energy

Question 50

What are the disadvantages of burning plastics (polymers)

Answer 50

Release greenhouse gases Releases toxic gases Expensive to build a maintain the plant

Question 51

What are the advantages of landfills?

Answer 51

No greenhouse gases Cheapest option

Question 52

What are the disadvantages of landfills?

Answer 52

Uses large area of land Remains for 1000s of years

Question 53

What are the different fractions in a fractional distillation column from hottest to coldest?

Answer 53

Bitumen, heavy fuel oil, diesel, kerosene, petrol, liquefied petroleum gases

Question 54

What temperature does cracking occur?

Answer 54

600 degrees

Question 55

Why is cracking necessary?

Answer 55

Smaller fractions are in more demand than large ones

Question 56

What chemical is used for cracking?

Answer 56

Aluminium oxide